Geography
The borders of South Gondor were the Ethir Anduin and the river Poros in the north, the river Harnen in the south, the Ephel Dúath and the river Harnen in the east and the Bay of Belfalas in the west. It was described as a "desert land" at the time of the War of the Ring. However, it is possible that this meant that it was a land that was deserted by its inhabitants because of the wars between Gondor and the Corsairs of Umbar and the Haradrim. It is possible that South Gondor had a climate that was fluctuating between mild winters and very hot and dry summers.
South Gondor was absorbed by Gondor during the height of its power, probably the expansions of Tarannon Falastur, who extended the sway of Gondor along the coasts west and south of the Mouths of Anduin.
South Gondor remained a part of Gondor until the Kin-strife after which it became a debatable land between the Corsairs of Umbar and the Kings of Gondor.
During the days of Steward Túrin II, the Haradrim occupied South Gondor and there was much fighting along the Poros. When they started invading Ithilien, many Rohirrim came to the support of Gondor so that Túrin won against the Haradrim at the Crossings of Poros in (T.A. 2885).